JPH1130355A - Opening and closing valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent liquid dropping from a discharge port of a liquid nozzle. SOLUTION: An opening and closing valve 40 has an ROM 245 in which a large number of valve closing program control patterns to prevent liquid dropping at the time of valve closing are memorized, and a control device 242 to control a valve body lift position in the valve closing direction by controlling electrifying quantity to a linear voice coil type drive device 134 in accordance with the valve closing program control patterns is furnished.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-off valve which is used in place of a suck-back valve, and more specifically, for example, when closing a valve, prevents liquid dripping from a discharge port of a fluid nozzle and applies fluid. The present invention relates to an on-off valve capable of stabilizing a fluid thickness on a surface.

[0002]

2. Description of the Related Art Conventionally, a suck-back valve has been used, for example, in a process of manufacturing a semiconductor wafer or the like. This suck back valve, when the supply of the coating liquid to the semiconductor wafer is stopped by urging the on-off valve,
It has a function of preventing a so-called dripping of a small amount of coating liquid from the discharge port of the fluid nozzle toward the semiconductor wafer.

Here, a suck-back valve according to the prior art is shown in FIG. Such a suck back valve is disclosed in, for example, Japanese Utility Model Publication No. Hei 8-10399. The suckback valve 10 has a valve body 18 in which a fluid passage 16 for communicating the fluid introduction port 12 and the fluid outlet port 14 is formed, and a bonnet 20 connected to an upper part of the valve body 18. In the fluid passage 16, for example, a diaphragm 26 formed of a material such as fluororesin is provided so as to be displaceable. A passage 19 for supplying and exhausting air in the chamber 17 when the diaphragm 26 is displaced communicates with the chamber 17 closed by the diaphragm 26. A thick portion 22 is formed at the center of the diaphragm 26, and a thin portion 24 is formed around the thick portion 22.

A protrusion 27 is formed on the upper part of the thick portion 22, and the protrusion 27 engages with a concave portion 29 defined at the lower end of the piston 30, and the diaphragm 26 is connected to the piston 30. Is done. The piston 30 has the valve body 1
A V-packing 32 that slides on the inner wall surface and performs a sealing function is mounted. Further, a spring 34 for constantly pressing the piston 30 upward is provided in the valve body 18. A compressed air supply port 28 is formed in the bonnet 20, and the compressed air supply port 28 is connected to a compressed air supply source (not shown) via a flow control valve (not shown) or the like. Reference numeral 36
Denotes an adjusting screw that adjusts the flow rate of the coating liquid sucked by the diaphragm 26 by adjusting the amount of displacement of the piston 30 by contacting the piston 30.

The operation of the suck-back valve 10 will be described briefly.
In a normal state in which the coating liquid is supplied toward 4, the compressed air is supplied from the compressed air supply source to the compressed air supply port 28 by controlling the flow control valve and the like. Therefore, the piston 30 is displaced downward by the pressure of the compressed air, and the diaphragm 26 connected to the piston 30
In FIG. 5, it protrudes into the fluid passage 16 as indicated by a two-dot chain line.

Therefore, when the flow of the coating liquid in the fluid passage 16 is stopped, the supply of the compressed air from the compressed air supply source to the compressed air supply port 28 is stopped by controlling the flow control valve and the like, so that the spring is stopped. The piston 30 and the diaphragm 26 rise integrally under the action of the resiliency of the diaphragm 34, contact the tip of the adjusting screw 36 to regulate its displacement, and the fluid passage 16 under the negative pressure of the diaphragm 26. A predetermined amount of the coating liquid remaining inside is sucked, and dripping at the supply port of the coating liquid connected to the fluid outlet port 14 is prevented.

[0007]

SUMMARY OF THE INVENTION The present invention relates to an on-off valve used in place of such a suck-back valve according to the prior art. It is an object of the present invention to provide an on-off valve which can prevent liquid dripping from the valve and does not require a suck-back valve.

[0008]

In order to achieve the above object, the present invention relates to an on-off valve for controlling the opening and closing of a flow path under the driving of an electric actuator. The first gradient with respect to the time until the body lift position reaches the predetermined valve body lift position and the first gradient from when the valve body lift position reaches the predetermined valve body lift position to when the valve is closed are calculated. Storage means for storing a plurality of valve-closing program control patterns for preventing liquid dripping at the time of valve closing corresponding to the characteristics of the fluid flowing through the flow path, determined by the second gradient with respect to the time that is also a gentle gradient. ,
Control means for controlling the amount of electricity supplied to the electric actuator in accordance with a valve closing program control pattern based on the characteristics of the fluid flowing through the flow path and controlling the amount of current supplied to the electric actuator to control the valve lift position in the valve closing direction. It is characterized by having.

According to the on-off valve of the present invention, the valve closing program control pattern is read from the storage means based on the characteristics of the fluid flowing through the flow path, and the valve lift is controlled according to the read valve closing program control pattern. The position is controlled to prevent dripping when the on-off valve is closed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An on-off valve according to the present invention will be described in detail below with reference to the accompanying drawings showing preferred embodiments.

In FIG. 1, reference numeral 40 denotes an on-off valve according to the present embodiment. This on-off valve 40 is a valve body 4
2 and a first port 4 is provided at one end of the valve body 42.
8 is formed, and a second port 50 is formed on the other end side. The first and second ports 48 and 50 are provided with connection members 54a and 54b with which the distal ends of the tubes 52a and 52b are engaged, respectively.
The ends of the tubes 52a, 52b engage with stepped portions 56a, 56b formed on the outer periphery of the tube 52b.
a, 52b are positioned. External threads 58a and 58b are threaded at the end of the valve body 42,
The tubes 52a, 52b are connected to the first port 48 and the second port 50 of the valve body 42 in a liquid-tight manner by screwing the lock nuts 60a, 60b into the a, 58b.

A fluid passage 62 for communicating the first port 48 and the second port 50 is provided inside the valve body 42.
And the fluid passage 62 communicates with a recess 66 defined in the valve body 42.

An on-off valve 40 faces the opening of the fluid passage 62 of the valve body 42. The on-off valve 40 is shown in FIG.
As shown in FIG. 2B, an on-off valve diaphragm 168 is provided which engages with a step 166 formed on the wall of the recess 66. The on-off valve diaphragm 168 is formed of the first thin film 1
70 and a second thin film member 172 are overlapped with each other, and a plurality of small holes 174 are defined in the second thin film member 172.

A thick portion 176 is formed at the center of the first thin film member 170.
When the thick portion 176 is displaced in the direction of arrow A due to the bending of the zero, the thick portion 176 is seated on the seating portion 180 formed at the opening of the fluid passage 62 to block the fluid passage 62. On the other hand, when the thick portion 176 is displaced in the direction of arrow B and separated from the seating portion 180, the first port 4
8 communicates with the second port 50. The thick part 176
A concave portion 182 having a substantially V-shaped cross section is defined at the upper portion of the upper portion, and a circumferential groove portion 184 is defined at the outer wall of the thick portion 176.

The valve body 42 is provided with a holding member 186 surrounding the valve body 42, and the first thin film member 170 and the second thin film member are formed by the holding member 186 and the step 166 of the valve body 42. The edge of body 172 is pinched. The holding member 186 includes the on-off valve diaphragm 168.
This forms a closed chamber 187. The holding member 186 defines a passage 188 communicating with the chamber 187, and the passage 188 communicates with the outside of the holding member 186. The holding member 186 is formed with a protrusion 190 that fits into the recess 66, and a hole 1 is formed in the center of the protrusion 190.
92 is defined. A thick portion 176 of the on-off valve diaphragm 168 is fitted into the hole 192, and a bush 194 is provided on a wall forming the hole 192.

A body 19 is provided above the holding member 186.
6 is fixed. A recess 198 communicating with the hole 192 is defined in the body 196, and an O-ring 200 is provided at an opening of the recess 198. A recess 204 communicating with the recess 198 through the hole 202 is formed at an upper portion of the body 196.

In the recess 204, as shown in FIG.
A linear voice coil type driving device 134 which is an electric actuator is provided. This linear voice coil type driving device 134 has a housing 136,
In the chamber 138 of 36, a long stem 140 is provided so as to be displaceable in the arrow A or B direction. A fixed iron core 142 is provided in the upper center of the chamber 138, and the fixed iron core 142 is provided.
Reference numeral 42 is formed so as to extend a predetermined length along the longitudinal direction of the housing 136.

The fixed iron core 1 is provided in the chamber 138.
The fixed pole magnet 14 fixed to the inner wall surface of the housing 136 via the support member 144 and separated from the fixed pole magnet 42 by a predetermined distance.
6 are provided. In this case, a substantially horizontal magnetic field is formed between the fixed pole magnet 146 and the fixed iron core 142. Further, a displacement member (bobbin) 15 around which an electromagnetic coil 148 is wound between the fixed iron core 142 and the fixed pole magnet 146.
The displacement member 150 is provided so as to be displaceable integrally with the stem 140 via a connecting pin (not shown). Also, a predetermined clearance is formed between the fixed iron core 142 and the displacement member 150. Reference numeral 152 indicates a lead wire for flowing a current from the control device 242 to the electromagnetic coil 148 to drive the stem 140.

A guide member 154 is provided on the inner wall surface of the housing 136 via the support member 144, and the guide member 154 engages with the concave portion 156 of the stem 140 to linearly move the stem 140. It guides and regulates the displacement of the stem 140.

An encoder (lift detecting means) 160 is fixed to an inner wall portion of the housing 136 opposite to the guide member 154 via a support member 158. The encoder 160 has a photosensor (not shown) fixed to the housing 136 side, and a glass scale (not shown) fixed to the stem 140 side with scale values formed on the glass substrate at regular intervals. In this case, the amount of displacement of the stem 140 is detected by a photo sensor (not shown) via a glass scale, and a pulse-like detection signal derived from the photo sensor is transmitted via a lead wire 162 to the control device 24.
2 is fed back.

The linear voice coil type driving device 134
A rod-shaped displacement member 206 is fixed to a lower portion of the stem 140, and the displacement member 206 is inserted into the hole 202 and the recess 198. As shown in FIG. 2A, a flange portion 208 is formed on the outer periphery of the displacement member 206, and a coil spring 2 is formed on an upper surface of the flange portion 208.
10 is seated, and the other end of the coil spring 210 is seated on the upper surface forming the recess 198.

Accordingly, the displacement member 206 is sequentially urged in the direction of arrow A by the coil spring 210. A conical portion 212 is formed at the tip of the displacement member 206, and the conical portion 212 is formed in the concave portion 18 of the thick portion 176.
2, the thick portion 176 is held by the conical portion 212 and the cylindrical member 216 screwed into the male screw 214 formed in the displacement member 206.

The stem 140 and the displacement member 206
And the opening / closing valve diaphragm 168 is indicated by an arrow A or B
By integrally displacing in the direction, it functions as a valve body of the on-off valve 40.

The control device 242 receives and counts the pulse-like detection signal output from the encoder 160, and counts the pulse count corresponding to the lift position of the valve body.
And the current value signal is amplified, and the amplified current is supplied to the electromagnetic coil 1
R that stores a current amplifier 244 for energizing the C. 48, a control program for controlling the central processing unit 246 described later, and a plurality of valve closing program control patterns at the time of valve closing.
Under the control of a control program stored in the ROM 245, the OM (storage means) 245 compares the valve lift position based on the count value of the pulse counter 243 with the valve lift position based on the valve closing program control pattern. A central processing unit 246 for obtaining the deviation and sending a current value signal based on the deviation to the current amplifier 244.

Here, the central processing unit 246 is provided with a timer means 246a for measuring time at predetermined time intervals.
A deviation calculating means 246b for obtaining a deviation between the valve body lift position based on the valve closing program control pattern and the valve body lift position based on the count value of the pulse counter 243 at every predetermined time, and a deviation calculating means 246b.
Value control means (current amount control means) for sending out a current value signal based on the deviation in order to make the deviation obtained by the method zero.
46c is provided functionally.

The current amplifier 2 excluding the ROM 245
44, pulse counter 243, timer means 246a, deviation calculating means 246b, and current value controlling means 246c
It functions as control means.

The on-off valve 40 according to the present embodiment is basically configured as described above. Next, the operation and effect of the on-off valve will be described.

First, as shown in FIG. 1, a tube 52a communicating with the first port 48 of the on-off valve 40 is provided with a coating liquid drop 234 provided with a fluid nozzle 234 for dropping the coating liquid toward the semiconductor wafer 230. Device 2
The coating liquid supply source 232 that stores the coating liquid dropped toward the semiconductor wafer 230 and supplies the coating liquid at a predetermined pressure is connected to the tube 52b communicating with the second port 50. Is done. In addition, the linear voice coil type driving device 134 and the encoder 160 have a control device 242, respectively.
Is connected.

Therefore, the control device 242 controls the on-off valve 4
When the 0 linear voice coil type driving device 134 is energized and a current flows through the electromagnetic coil 148, an electromagnetic force is generated in the electromagnetic coil 148. Fixed pole magnet 146 and fixed iron core 142
And the electromagnetic force, the displacement member 150 around which the electromagnetic coil 148 is wound and the stem 140 are integrally displaced in the direction of arrow A according to the so-called Fleming's left-hand rule. This electromagnetic force can be adjusted to a desired magnitude and duration by appropriately adjusting the magnitude of the current flowing through the electromagnetic coil 148.
The direction of the force can be changed in the direction of arrow A or B by reversing the polarity of the current flowing through the arrow.

When the stem 140 is displaced in the direction of arrow B in this manner, the displacement member 206
Displacement against the elastic force of 10
By separating the thick portion 176 from the seating portion 180, the first port 48 and the second port 50 communicate with each other.

When the coating liquid supply source 232 is energized through the preparatory steps as described above, the coating liquid is supplied from one of the tubes 52b to the coating liquid dropping device 236 through the fluid passage 62, and is supplied from the fluid nozzle 234 to the semiconductor. It is dropped on the wafer 230. As a result, a film (not shown) having a desired film thickness is formed on the semiconductor wafer 230.

Next, the case where the on-off valve 40 is closed will be described with reference to the flowchart of FIG.

When the opening / closing valve 40 is instructed to open, the execution of the program is started, and the viscosity instruction signal and the surface tension instruction signal set for the coating liquid as a fluid are read into the control device 242 ( Step S
1).

Further, the valve closing program control pattern specifically includes, in addition to the viscosity and surface tension of the coating liquid, the pressure of the coating liquid sent from the coating liquid supply source 232, the ambient temperature, and the on-off valve 40.
Is also affected by the volume from the coating liquid dropping device 236 to the tip of the fluid nozzle 234. However, in the device provided with the on-off valve 40 of the present example, the pressure of the coating liquid supplied from the coating liquid supply source 232, Since the ambient temperature and the volume from the on-off valve 40 to the tip of the fluid nozzle 234 via the coating liquid dropping device 236 are determined before the on-off valve 40 is mounted, these are determined by the valve closing program control pattern stored in the ROM 245. It is assumed that the information has already been reflected, and an example is given of a case where only the change of the coating liquid to be used is dealt with.

Following execution of step S1, the on-off valve 40 is controlled to be open.

Subsequent to the control of the open state of the on-off valve 40 following step S1, a corresponding valve-closing program control pattern is read out from the ROM 245 based on the read-in viscosity signal and the surface tension command signal of the coating liquid. Then, the valve closing program control pattern is transferred to and stored in a RAM (not shown) (step S2). FIG. 4 shows an example of the valve closing program control pattern.

As is apparent from FIG.
It indicates the valve opening degree relative to the elapsed time from 0, that is, the lift position of the valve body. Until the lift position of the valve body reaches the position P1, the valve is moved in the valve closing direction at a predetermined steep gradient with respect to time. After the position P1 is reached, a valve closing program control pattern is set to move the valve in the valve closing direction at a predetermined gentle gradient with respect to time until closing. The reason for adopting such a valve closing program control pattern will be described later.

Waiting for the instruction to close the valve following step S2 (step S3), when the instruction to close the valve is issued, the timer 246a starts counting time (step S3).
4) Subsequently, the count value of the pulse counter 243 is read (step S5). Subsequent to step S5, it is checked whether the valve body has reached the fully closed position (step S5).
6).

If it is determined in step S6 that the valve body has not reached the fully closed position, the valve closing position corresponding to the next time measured by the timer means 246a is determined by referring to the valve closing program control pattern. It is read from the valve closing program control pattern (step S7), and the deviation between the valve body lift position read in step S7 and the valve body lift position based on the count value of the pulse counter 243 is determined (step S8). ), A current value control signal is sent to the current amplifier 244 based on the deviation obtained in step S8 (step S9).

The current amplifier 2 receiving the current value control signal
The current having the current value output from 44 is sent to the electromagnetic coil 148, and the valve body is driven in the valve closing direction. This state is continued until the predetermined time has elapsed (step S10). If it is determined in step S10 that the next time has elapsed, the process proceeds to step S10.
Is repeated from step S5 and executed again.

The above-described repetition is repeatedly performed in the valve closing direction until it is determined in step S6 that the valve body has reached the fully closed position.

Here, the reading of the valve body lift position corresponding to the time measured next to the time at which the valve body lift position was read in step S5 from the valve closing program control pattern in the following step S7 is the start of valve closing. This is because the current value control signal is immediately transmitted at the time (t0).

Therefore, after a predetermined amount of the coating liquid is applied to the semiconductor wafer 230, the control device 242 drives the on-off valve 40 in the valve closing direction. The linear voice coil type driving device 134 is urged to follow the above-described valve closing program control pattern, and the stem 140 is moved to the direction indicated by the arrow A.
2A, the thick portion 176 of the on-off valve diaphragm 168 sequentially moves in the direction of the seating portion 180, and finally comes into contact with the first port 48 and the second port 50. Communication with is interrupted. Therefore, the dropping of the coating liquid onto the semiconductor wafer 230 from the fluid nozzle 234 of the coating liquid dropping device 236 is stopped.

The valve closing pattern of the valve body when controlled by the above-described valve closing program control pattern follows the valve closing program control pattern shown in FIG. In this case, when a valve closing instruction is given from the state where the valve body is open, the valve body is driven in the valve closing direction at a steep gradient to the position P1, and the valve body reaches the position P1 in a short time. When the position P1 is reached, the valve is gradually closed in the direction to close the valve.
It is driven until the valve closes.

Here, the dripping of the coating liquid when the on-off valve 40 is controlled to be closed by the valve closing program control pattern will be described.

At the start of valve closing, the fluid nozzle 234
The coating liquid immediately before being dropped on the semiconductor 230 remains therein. In this state, when the lift position of the valve body is rapidly lowered to the position P1, and then the valve body is sequentially driven in the valve closing direction with a gentle gradient, the fluid nozzle 23 starts to close.
The coating liquid remaining in 4 remains in the pipe from the on-off valve 40 to the fluid nozzle 234,
Experiments have confirmed that the fluid nozzle 234 does not fall down as a liquid dripping.

In this case, the gradient from the valve opening to the position P1 and the gradient in the valve closing direction from the position P1 to the valve closing are based on the viscosity and the surface tension of the coating liquid. Characteristics such as viscosity and surface tension of liquid, pressure of coating liquid and fluid nozzle 2
It was found that it was determined based on the capacity up to 34 tips.

That is, the amount of the coating liquid passing through the on-off valve 40 is rapidly reduced by driving the on-off valve 40 steeply to the position P1 close to the closing of the valve. The maximum pressure generated by the water hammer phenomenon is reduced due to the presence of the coating liquid flowing out of the on / off valve 40, and the amount of the coating liquid flowing out of the on / off valve 40 is small, and the coating liquid remaining in the fluid nozzle 234 from the on / off valve 40 is removed. The liquid does not drip from the fluid nozzle 234 against the surface tension of the coating liquid. Further, since the valve body is sequentially closed from the position P1 close to the valve closing to the closing with a gentle gradient, the coating liquid passing through the on-off valve 40 gradually decreases and stays in the fluid nozzle 234 from the on-off valve 40. This is probably because the applied coating liquid does not have kinetic energy enough to discharge the coating liquid from the fluid nozzle 234 against the surface tension of the coating liquid and does not cause dripping.

As described above, the valve closing program control pattern, that is, the position P1, the moving gradient from the open position of the on-off valve 40 to the position P1 of the valve body, and the gradient from the position P1 to the valve closing are represented by the temperature and the pressure of the coating liquid. By setting the volume of the pipe, the viscosity of the coating liquid, the surface tension, and the like, it is possible to prevent the coating liquid from dripping.

The linear voice coil type driving device 13
4 is an electric control, so that the displacement of the stem 140 can be easily and accurately controlled. Therefore, as shown by the solid line in FIG. 4, the diaphragm 168 can be smoothly displaced.

The control device 242 controls the displacement of the stem 140 based on a signal corresponding to the displacement amount of the stem 140 input from the encoder 160 of the linear voice coil type driving device 134. 168 can be controlled with high precision, and therefore, the amount of the coating liquid sucked by the on-off valve 40 can be controlled with high precision.

Further, in this embodiment, the electric actuator is the linear voice coil type driving device 134. However, the present invention is not limited to this. For example, a linear DC motor or a linear pulse motor may be used. An electric linear actuator may be used in which a ball screw is provided on the rotation shaft of the stepping motor, and the rotational motion of the ball screw is converted into linear motion by a displacement member.

[0053]

According to the opening / closing valve of the present invention, the valve lift position is driven to the predetermined valve lift position by the first gradient based on the fluid characteristic from the time of the valve closing instruction, and the valve lift position is set. Is driven to the valve closing position by the second gradient based on the characteristic of the fluid that is gentler than the first gradient from when the valve reaches the predetermined valve body lift position, and is connected to the outlet side of the on-off valve. An effect is obtained that no dripping occurs when the valve is closed from the fluid nozzle to be closed. Therefore, an effect is obtained that a suck-back valve that is conventionally connected to the on-off valve to prevent dripping from the fluid nozzle becomes unnecessary.

[Brief description of the drawings]

FIG. 1 is a schematic configuration sectional view showing an on-off valve according to an embodiment of the present invention.

FIG. 2A is a partially enlarged longitudinal sectional view of an on-off valve;
FIG. 2B is a partially enlarged sectional view showing details of the diaphragm in FIG. 2A.

FIG. 3 is a flowchart for explaining an operation when the on-off valve according to the embodiment of the present invention is closed.

FIG. 4 is a schematic diagram showing a valve closing program control pattern of the on-off valve according to the embodiment of the present invention;

FIG. 5 is a schematic longitudinal sectional view showing an on-off valve according to the related art.

[Explanation of symbols]

Reference Signs List 40 ... On-off valve 42 ... Valve body 62 ... Fluid passage 168 ... Diaphragm 134 ... Linear voice coil type driving device 140 ... Stem 160 ... Encoder 206 ... Displacement member 230 ... Semiconductor wafer 232 ... Coating liquid supply source 234 ... Fluid nozzle 236 ... Coating Dropping device 242 ... Control device 243 ... Pulse counter 244 ... Current amplifier 245 ... RO
M 246 central processing unit 246a timer unit 246b deviation calculation unit 246c current value control unit

Claims (5)

[Claims] 1. An on-off valve for controlling the opening and closing of a flow path under the drive of an electric actuator, wherein an opening / closing valve is instructed to close from a time until a valve lift position reaches a predetermined valve lift position. A closing determined by a first slope and a second slope for a time that is gentler than the first slope from when the valve element lift position reaches the predetermined valve element lift position to when the valve is closed is determined. Storage means for storing a plurality of valve-closing program control patterns for preventing liquid dripping at the time of valve operation in accordance with the characteristics of the fluid flowing through the flow path; and reading out from the storage means based on the characteristics of the fluid flowing through the flow path. Control means for controlling the amount of current supplied to the electric actuator in accordance with the valve closing program control pattern to control the valve body lift position in the valve closing direction. 2. The on-off valve according to claim 1, wherein the characteristics of the fluid include viscosity and surface tension of the fluid. 3. The on-off valve according to claim 1, wherein the predetermined valve body lift position, the first gradient and the second gradient are determined based on the viscosity and surface tension of the fluid. On-off valve. 4. The on-off valve according to claim 1, wherein the control means includes a lift detecting means for detecting a valve element lift position, and a valve element based on the valve element lift position detected by the lift detecting means and a valve closing program control pattern. An on-off valve comprising: a deviation calculating means for obtaining a deviation from a lift position; and a current amount control means for sending a current amount based on the deviation obtained by the deviation calculating means to an electric actuator. 5. The on-off valve according to claim 4, wherein the lift detecting means includes an encoder mounted on a stem of the on-off valve, and a counter for counting an output of the encoder.